Crazy that after I interacted with you, I saw the OP post, liked it, and now see it again because you're sharing it. Are communities built within some interactive parameters? Like, did a single interaction with you cause me to be more likely to see similar things to what you would see?

Well this depends on the app that you use, and how it handles things. And i am not 100% sure as to what you mean, but in general; yes, it is called 'web of trust'. You have to understand that because there is no authoritative server or anything, and anyone and anything can just spin up endless amounts of profiles trivially, it is utter chaos. You app will, one way or another, try to differentiate signal from noise, and the most organic way to do that is to use things like follow-lists and interactions people have.